Add getter for statusUrl and fix trigger bug.

When a whitelisted member would add the retest phrase then triggered was being set

src/main/java/org/jenkinsci/plugins/ghprb/GhprbPullRequest.java

@@ -321,7 +321,6 @@ private void checkComment(GHIssueComment comment) throws IOException {
             } else if (accepted && helper.isWhitelisted(sender)) {
                 logger.log(Level.FINEST, "Retest accepted and user {0} is whitelisted", sender);
                 shouldRun = true;
-                triggered = true;
             }
         } else if (helper.isTriggerPhrase(body)) { // trigger phrase
             logger.log(Level.FINEST, "Trigger phrase");

src/main/java/org/jenkinsci/plugins/ghprb/extensions/status/GhprbSimpleStatus.java

@@ -66,6 +66,10 @@ public GhprbSimpleStatus(
         this.completedStatus = completedStatus;
     }
 
+    public String getStatusUrl() {
+        return statusUrl == null ? "" : statusUrl;
+    }
+
     public String getCommitStatusContext() {
         return commitStatusContext == null ? "" : commitStatusContext;
     }